. The prevalence and incidence is approximately 0.1%-0.4%. Although the condition is benign, it may be associated with more serious conditions such as HIV and malignancy. GA affects women more frequently than men but can affect any age group, although it most commonly presents in those ages 30 years and younger. While the exact etiology is unknown, GA has been most strongly associated with diabetes mellitus, hyperlipidemia, and autoimmune diseases.
Courtesy Lucas Shapiro and Dr. Bilu Martin
The disease presents as localized, annular erythematous plaques and papules on the dorsal hands and feet in approximately 75% of cases. However, eruptions may appear on the trunk and extremities and can be categorized into patchy, generalized, interstitial, subcutaneous, or perforating subtypes. The lesions are often asymptomatic and typically not associated with any other symptoms.
Courtesy Lucas Shapiro and Dr. Bilu Martin
The pathogenesis of GA is still under investigation, but recent studies suggest that a Th1-mediated dysregulation of the JAK-STAT pathway may contribute to the disease. Other hypotheses include a delayed hypersensitivity reaction or cell mediated immune response. The mechanism may be multifaceted, and epidemiologic research suggests a genetic predisposition in White individuals, but these findings may be associated with socioeconomic factors and disparities in health care.
GA presents on histology with palisading histiocytes surrounding focal collagen necrobiosis with mucin deposition. Tissue samples also display leukocytic infiltration of the dermis featuring multinucleated giant cells. There are defining features of the different subtypes, but focal collagen necrosis, the presence of histiocytes, and mucin deposition are consistent findings across all presentations.
GA lesions commonly regress on their own, but they tend to recur and can be functionally and visually unappealing to patients. The most common treatments for GA include topical corticosteroids, intralesional corticosteroid injections, and other anti-inflammatory drugs. These interventions can be administered in a variety of ways as the inflammation caused by GA exists on a spectrum, and less severe cases can be managed with topical or intralesional treatment. Systemic therapy may be necessary for severe and recalcitrant cases. Other interventions that have shown promise in smaller studies include phototherapy, hydroxychloroquine, and TNF-alpha inhibitors.
Dr. Donna Bilu Martin
This case and photo were submitted by Lucas Shapiro, BS, Nova Southeastern University College of Osteopathic Medicine, Tampa Bay Regional Campus, and Dr. Bilu Martin.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at mdedge.com/dermatology. To submit a case for possible publication, send an email to dermnews@mdedge.com.
References
Joshi TP and Duvic M. Am J Clin Dermatol. 2022 Jan;23(1):37-50. doi: 10.1007/s40257-021-00636-1.
Muse M et al. Dermatol Online J. 2021 Apr 15;27(4):13030/qt0m50398n.
Schmieder SJ et al. Granuloma Annulare. NIH National Center for Biotechnology Information [Updated 2022 Nov 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. 7.